Technical Field
The present invention relates to integrated circuit processing, and more particularly to methods for growing a metal on a dielectric material with reduced or eliminated agglomeration.
Description of the Related Art
Growing a thin film of metal on top of a dielectric is challenging, since the metal does not wet a surface of the dielectric, and instead balls up into small agglomerations. This makes the film rough (or perhaps even discontinuous), and hence unusable.
In a magnetic tunnel junction, one magnetic metal layer must be grown on top of an oxide tunnel barrier, such as a top CoFeB layer in a CoFeB/MgO/CoFeB structure. In another example, for magnetic tunnel junctions used in spin torque magnetoresistive random access memory (MRAM), a free layer needs to be sandwiched in between an oxide cap and an oxide seed layer, for example, a free layer (CoFeB) is sandwiched between MgO layers (e.g., oxide seed layer (MgO)/free layer (CoFeB)/oxide cap layer (MgO)/CoFeB). Other examples and applications in thin film technology outside of MRAM devices also suffer from similar constraints when forming metal on dielectric.